4. Stateless and Stateful Address Configuration
To simplify host configuration, IPv6 supports both stateful
address configuration (as in the presence of a DHCP server)
and stateless address configuration (as in the absence of
a DHCP server).
With stateless address configuration, hosts on a link
automatically configure themselves with IPv6 addresses for
the link (called link-local addresses) and with addresses
that they derive from prefixes that local routers advertise.
Even in the absence of a router, hosts on the same link
can configure themselves with link-local addresses and communicate
without manual configuration.
5. Built-in Security
The IPv6 protocol suite requires support for IPSec. This
requirement provides a standards-based solution for network
security needs and promotes interoperability between different
IPv6 implementations.
6. Better Support for QoS
New fields in the IPv6 header define how traffic is handled
and identified. Traffic identification (using a Flow Label
field in the IPv6 header) allows routers to identify and
provide special handling for packets belonging to a flow,
which is a series of packets between a source and a destination.
Because the IPv6 header identifies the traffic, QoS can
be supported even when the packet payload is encrypted through
IPSec.
7. New Protocol for Neighboring Node Interaction
The Neighbor Discovery protocol for IPv6 is a series of Internet
Control Message Protocol for IPv6 (ICMPv6) messages that manage
the interaction of nodes on the same link (known as neighboring
nodes). Neighbor Discovery replaces the broadcast-based Address
Resolution Protocol (ARP), ICMPv4 Router Discovery, and ICMPv4
Redirect messages with efficient multicast and unicast Neighbor
Discovery messages.
8. Extensibility
IPv6 can easily be extended by adding extension headers after
the IPv6 header. Unlike options in the IPv4 header, which can
support only 40 bytes of options, the size of IPv6 extension
headers is constrained only by the size of the IPv6 packet.
10. Communication Types for
IPv6
There are three types of communication for IPv6
1. Unicast : used for one-to-one communication. A
unicast address identifies a single network interface. The protocol
delivers packets sent to a unicast address to that specific
interface.
There are 3 types of unicast addresses namely global, unique-local
and link-local
2. Multicast : used for one-to-many communication.
Multicast address is also assigned to a set of interfaces that
typically belong to different nodes. A packet that is sent to
a multicast address is delivered to all interfaces identified
by that address. Multicast addresses are easily identifiable
because the value of a IPv6 multicast address begins with "FF"
3. Anycast : used for one-to-one-of-many communication
An anycast address is assigned to a group of interfaces, usually
belonging to different nodes. A packet sent to an anycast address
is delivered to just one of the member interfaces, typically
the “nearest” according to the routing protocol’s
choice of distance.
An important point to note here is that broadcast communication
type is eliminated from IPv6 which was there in IPv4.
Broadcasts can be thought of as a special case of multicasting,
where every device is the intended recipient. In IPv4, sending
a broadcast causes all devices to process the packet, even those
that are not concerned with the contents. Using multicasts is
much more efficient because the packets can be targeted to a
subset of devices, such as routers running Open Shortest Path
First (OSPF).
